Abstract

Wetland is a part of natural ecosystem that provides many intangible services to human. However, many of these wetlands have been destroyed and converted to other land uses. Beaufort, Sabah, consists of an extensive wetland ecosystem. This wetland ecosystem lays pieces of pristine peat swamp forest (PSF) that has been degraded due to human activities. This study aims at examining the dynamics of
wetland vegetation changes in relation to anthropogenic activities in Beaufort area. Multitemporal satellite data of landsat MSS (June 29, 1985), Landsat TM (June 14, 1991), Landsat 7 ETM+ (November 2, 1999), Landsat 7 ETM+ (Jan 14, 2003) and SPOT4-HRVIR (March 26, 2003) were used in this study. A supervised classification approach was performed to classify satellite images into ten land cover types. The overall accuracies for all classifications are more than 89%. The result from the land cover classification shows a Significant changes to PSF, bareland and grassland
cover type throughout the 18-year period. The PSF had drastically plummeted by about 70% from 1985 to 2003. The grassland had almost doubled from 1985 to 2003 and bareland also increased more than 100%. These changes were mainly
due to fires occurred in 1998 and 2003 during El-Nino event. The El-Nino fires did not affect the mangrove. The dynamics change pattern analysis showed that the PSF area has severely degraded, leading to deforestation. The main dynamic pattern indicate that the PSF areas have changed to grassland and bareland from 1985 to 2003. Fragmentation analysis based on mean patch size and largest patch index provide the evidence that the PSF has undergone an increase of fragmentation between 1985 to March 2003. The mean nearest neighbour distance value has increased indicating that the patches of PSF have low connectivity and
become more Isolated. Buffering and overlay analysis showed that agriculture was the main factor contributing to deforestation in Beaufort area. Questionnaire survey
discovered that El-Nino fires in 1998 and 2003 was due to land clearing for plantation using slash and burn. In short, the PSF in Beaufort area has been decreasing at an alarming rate due to uncontrolled human activities. Therefore, the
authorities such as Sabah Forestry Department are suggested to take action in controlling and managing the human activities for agriculture near the PSF especially during dry season.